Lubricating Composition

ABSTRACT

There is disclosed a lubricant composition comprising a major amount of a base oil and a minor amount of an additive composition comprising (i) a triazole compound substituted with an aryl moiety; (ii) a nitrogen-containing compound represented by the formula (I): 
     
       
         
         
             
             
         
       
     
     wherein R 1  and R 2  are each independently selected from the group consisting of at least one aryl moiety comprising from about 6 to about 30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substituted hydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenolic compound.

FIELD OF THE DISCLOSURE

The present disclosure is directed to additive and lubricantcompositions and methods for use thereof. More particularly, thisinvention is directed to an additive composition comprising (i) atriazole compound, (ii) a nitrogen-containing compound, and (iii) aphenolic compound.

BACKGROUND OF THE DISCLOSURE

Lubricating oils as used in the internal combustion engines andtransmissions of automobiles or trucks are subjected to a demandingenvironment during use. This environment results in oxidation of the oilwhich is catalyzed by the presence of impurities in the oil, and is alsopromoted by the elevated temperatures of the oil during use.

The oxidation of lubricating oils contributes to the formation of sludgein oils and the breakdown of viscosity characteristics of the lubricant.The oxidation is often controlled to some extent by selecting the properantioxidant additives thereby significantly improving the life of thelubricating oils. Antioxidant additives can extend the useful life ofthe lubricating oil by, for example, reducing or preventing unacceptableviscosity increases and/or deposit formation.

Additionally, protecting the metal surface of an engine against weardegradation by selecting the proper balance of antiwear agents in alubricating composition can significantly increase the life of the metalsurface. Antiwear agents form a thin-film on metal surfaces whichprevents metal to metal contact, resulting in a decrease in the amountof wear. A well-known and commonly used antiwear agent is zincdialkyldithiophosphate (ZDDP).

However, the demanding environment in which lubricating oils aresubjected, including high temperatures and/or high pressures, decomposeZDDP in a lubricating oil composition. Studies have shown that someexhaust emission catalysts can be deactivated by phosphorus, largelyderived from ZDDP compounds which have been the mainstay antiwear agentsin passenger car motor oil and heavy duty diesel formulations for thepast 50 years. Consequently, future engine oils will likely containreduced phosphorus levels. Furthermore, as ZDDP decomposes and releaseszinc molecules, these zinc molecules are capable of reacting with otherperformance additives present in the lubricating composition, creatingsludge and other particulate matter that can cause adverse effects onengine performance. These undesirable effects of oxidation presentproblems in meeting ever more severe engine performance requirements.

Simply lowering the amount of ZDDP is not a practical solution to theproblem because of the accompanying reduction of antiwear properties.Therefore, it would be desirable for a lubricating oil composition tocomprise improved additives that reduce the oxidative degradation oflubricating oils. It has now been discovered that a compositioncomprising (i) a triazole compound substituted with an aryl moiety, (ii)a nitrogen-containing compound, and (iii) a phenolic compound canprovide a highly effective system which can inhibit oxidation.

SUMMARY OF THE DISCLOSURE

In accordance with the disclosure, there is provided an additivecomposition comprising (i) a triazole compound substituted with an arylmoiety; (ii) a nitrogen-containing compound represented by the formula(I):

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenoliccompound.

In an aspect, there is also provided a lubricant composition comprisinga a major amount of a base oil; and a minor amount of an additivecomposition comprising (i) a a triazole compound substituted with anaryl moiety; (ii) a nitrogen-containing compound represented by theformula (I):

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenoliccompound.

Moreover, there is provided a method of decreasing oxidation degradationof a lubricant composition, said method comprising providing to amachine a lubricant composition comprising a major amount of a base oil;and a minor amount of an additive composition comprising (i) a triazolecompound substituted with an aryl moiety; (ii) a nitrogen-containingcompound represented by the formula (I):

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenoliccompound.

Further, there is provided a method for operating a machine, said methodcomprising adding to the machine a lubricant composition comprising amajor amount of a base oil; and a minor amount of an additivecomposition comprising (i) a triazole compound substituted with an arylmoiety; (ii) a nitrogen-containing compound represented by the formula(I):

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenoliccompound.

Furthermore, there is provided a method of lubricating at least onemoving part of a machine, said method comprising contacting the at leastone moving part with a lubricant composition comprising a major amountof a base oil; and a minor amount of an additive composition comprising(i) a triazole compound substituted with an aryl moiety; (ii) anitrogen-containing compound represented by the formula (I):

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenoliccompound.

Additional objects and advantages of the disclosure will be set forth inpart in the description which follows, and/or can be learned by practiceof the disclosure. The objects and advantages of the disclosure will berealized and attained by means of the elements and combinationsparticularly pointed out in the appended claims.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the disclosure, as claimed.

DESCRIPTION OF THE EMBODIMENTS

The present disclosure generally relates to a lubricant compositioncomprising a major amount of a base oil; and a minor amount of anadditive composition comprising (i) a triazole compound substituted withan aryl moiety; (ii) a nitrogen-containing compound represented byformula (I):

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenoliccompound.

As used herein, the term “major amount” is understood to mean an amountgreater than or equal to 50 wt. %, for example from about 80 to about 98wt. % relative to the total weight of the composition. Moreover, as usedherein, the term “minor amount” is understood to mean an amount lessthan 50 wt. % relative to the total weight of the composition.

As used herein, “aromatic” or “aryl”, unless expressly stated otherwise,refers to the typical substituted or unsubstituted non-aliphatichydrocarbyl or heterocyclic moieties of this class, e.g., apolyunsaturated, typically aromatic, hydrocarbyl cyclical, orheterocyclic, substituent, which can have a single ring or multiplerings (up to three rings) that are fused together or linked covalently.Typical hydrocarbyl aromatic moieties include phenyl, naphthyl,biphenylenyl, phenanthrenyl, phenalenyl, and the like. Such moieties areoptionally substituted with one or more hydrocarbyl substituents. Alsoincluded are aryl moieties substituted by other aryl moieties, such asbiphenyl. Heterocyclic aryl or aromatic moieties refers to unsaturatedcyclical moieties containing carbon atoms in the ring and additionallyone or more hetero atoms, which are typically oxygen, nitrogen, sulfurand/or phosphorus, such as pyridyl, thienyl, furyl, thiazolyl, pyranyl,pyrrolyl, pyrazolyl, imidazolyl, pyrazinyl, thiazolyl, etc. Suchmoieties are optionally substituted with one or more substituents suchas hydroxy, optionally substituted lower alkyl, optionally substitutedlower alkoxy, amino, amide, ester moieties and carbonyl moieties (e.g.,aldehyde or ketonic moieties).

As used herein, “alkaryl”, unless expressly stated otherwise, refers toan alkyl moiety substituted by the typical substituted or unsubstitutednon-aliphatic hydrocarbyl or heterocyclic moieties described above.Typical aryl moieties include phenyl, naphthyl, benzyl, and the like.Such moieties are optionally substituted with one or more substituentssuch as hydroxy, optionally substituted alkyl, optionally substitutedalkoxy, amino, amide, ester moieties and carbonyl moieties (e.g.,aldehyde or ketonic moieties).

As used herein, the terms “hydrocarbon”, “hydrocarbyl” or “hydrocarbonbased” mean that the moiety being described has predominantlyhydrocarbon character within the context of this invention. Theseinclude moieties that are purely hydrocarbon in nature, that is, theycontain only carbon and hydrogen. They can also include moietiescontaining substituents or atoms which do not alter the predominantlyhydrocarbon character of the moiety. Such substituents can include halo,alkoxy, nitro, etc. These moieties also can contain hetero atoms.Suitable hetero atoms will be apparent to those skilled in the art andinclude, for example, sulfur, nitrogen, oxygen, and phosphorus.Therefore, while remaining predominantly hydrocarbon in character withinthe context of this invention, these moieties can contain atoms otherthan carbon present in a chain or ring otherwise composed of carbonatoms.

A triazole compound suitable for use in the compositions of the presentdisclosure can be any triazole substituted with an aryl moiety. In someembodiments the triazole compound is an aryl-substituted 1,2,3-triazolecompound. In other embodiments the triazole compound is anaryl-substituted 1,2,4-triazole compound. In another embodiment, thetriazole compound is not an alkyl bis-3-amino-1,2,4-triazole.

As an example, the triazole compound can be substituted with asubstituted or unsubstituted aryl moiety comprising a single ring ormultiple rings, for example covalently linked rings. Non-limitingexamples of substituted aromatic moieties comprising covalently linkedrings include biphenyl, 1,1′-binaphthyl, p,p′-bitolyl, biphenylenyl, andthe like. As another example, the aryl moiety can comprise multiplefused rings. Non-limiting examples of aryl moieties comprising multiplefused rings include naphthyl, anthryl, pyrenyl, phenanthrenyl,phenalenyl, and the like. As a further example, the aryl moiety cancomprise a single ring covalently linked to the triazole. Non-limitingexamples of aryl moieties comprising a single ring covalently linked tothe triazole include phenyl and the like. As another example, the arylmoiety can comprise a single ring fused to the triazole. Non-limitingexamples of aryl moieties comprising a single ring fused to the triazoleinclude benzotriazole and tolyltriazole. An example of a commerciallyavailable triazole compound suitable for use herein is a benzotriazole,which is an off-white solid having a melting point ranging from 95-99°C., a flashpoint of 170° C., and a water solubility of 25 g/L at 20° C.The triazole compound can be combined/reacted/mixed with other additivesin order to increase its solubility in a composition.

In an embodiment, the triazole compound can be represented by formula(II) below:

wherein R³ is selected from the group consisting of hydrogen and analkyl moiety comprising from about 1 to about 24 carbon atoms, andwherein R⁴ is selected from the group consisting of hydrogen, an alkylmoiety comprising from about 1 to about 24 carbon atoms, and asubstituted hydrocarbyl moiety. In another embodiment, R³ and R⁴ of thetriazole compound represented by formula (II) can each independentlycomprise from about 1 to about 16 carbon atoms.

The triazole compound can be present in the disclosed lubricant andadditive compositions in any effective amount, which can be readilydetermined by one of ordinary skill in the art. In an embodiment, thelubricating composition of the present disclosure can comprise fromabout 0.05 wt. % to about 0.5 wt. %, and for example from about 0.1 wt.% to about 0.3 wt. % of the triazole compound, relative to the totalweight of the lubricating composition. In another embodiment, theadditive composition of the present disclosure can comprise from about0.48 wt. % to about 5 wt. % of the triazole compound, relative to thetotal weight of the additive composition.

The disclosed composition can also comprise a nitrogen-containingcompound for various uses. There is no particular restriction on thetype of nitrogen-containing compound that can be used in the disclosedcomposition of the present disclosure. Generally, a nitrogen-containingcompound suitable for use herein can be represented by formula (I)below:

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono. For example, R¹ andR² can each independently comprise an aryl moiety comprising from about6 to about 30 carbon atoms. Non-limiting examples of aryl moieties whichcan comprise R¹ and R² include phenyl benzyl, naphthyl, and alkaryl. Asanother example, R¹ and R² can each independently comprise alkaryl, suchas alkphenyl or alknaphthyl, wherein the alkyl moiety comprises fromabout 4 to about 30 carbon atoms, and for example from about 4 to about12 carbon atoms. As still another example, R¹ and R² can eachindependently comprise a substituted or unsubstituted aryl moiety.Non-limiting examples of substituents for the aryl moiety can include analkyl moiety comprising from about 1 to about 20 carbon atoms, hydroxyl,carboxyl, and nitro moieties. As another example, R¹ and R² can eachindependently be an alkyl substituted benzyl, phenyl, or naphthyl.

Other non-limiting examples of nitrogen-containing compounds that aresuitable include: phenylamine; diphenylamine; triphenylamine; variousalkylated phenylamines, diphenylamines and triphenylamines;N,N′-bis(4-aminophenyl)-alkylamine; 3-hydroxydiphenylamine;N-phenyl-1,2-phenylenediamine; N-phenyl-1,4-phenylenediamine;dibutyldiphenylamine; dioctyidiphenylamine; dinonyldiphenylamine;phenyl-alpha-naphthylamine; phenyl-beta-naphtylamine;diheptyldiphenylamine; and p-oriented styrenated diphenylamine.Additional non-limiting examples of suitable nitrogen-containingcompounds and their methods of preparation include those in U.S. Pat.No. 6,218,576, which descriptions are incorporated herein by reference.

The nitrogen-containing compounds used herein can comprise a structureother than that shown above in formula (I) which shows but one nitrogenatom in the molecule. Thus, the nitrogen-containing compound cancomprise a different structure provided that at least one nitrogen hasat least one aryl moiety attached thereto, e.g., as in the case ofvarious diamines having a secondary nitrogen atom as well as an arylattached to one of the nitrogens.

The nitrogen-containing compounds used herein can have antioxidantproperties in the disclosed compositions when used alone or incombination as described herein. The nitrogen-containing compounds usedherein should be soluble in a final lubricant composition.

The amount of the nitrogen-containing compound in the lubricatingcompositions can vary depending upon specific requirements andapplications. In an embodiment, the lubricating composition of thepresent disclosure can comprise from about 0.2 wt. % to about 1.2 wt. %,and for example from about 0.4 wt. % to about 1.0 wt. %, of thenitrogen-containing compound, relative to the total weight of thelubricating composition. In another embodiment, the additivecompositions of the present disclosure can comprise from about 2 wt. %to about 12 wt. % of the nitrogen-containing compound, relative to thetotal weight of the additive composition.

A phenolic compound suitable for use in compositions of the presentdisclosure can be any phenol, provided that it is soluble in a lubricantcomposition. For example, the phenolic compound can be substituted atone or both ortho positions. Examples of such phenolic compounds include2-tert-butylphenol, 2-ethyl-6-methylphenol, 2,6-di-tert-butyl-phenol,2,6-di-tert-butyl-4-methylphenol,2,2′-methylene-bis-4,6di-tert-butyl-phenol, 4,4′-methylene-bis(2,6-di-tert-butyl-phenol),2,2′-propylidene-bis(6-tert-butyl-4-methylphenol), and mixtures thereof.As another example, the phenolic compound can be an esterified reactionproduct of a phenol and an unsaturated carboxylic acid comprising atleast one double bond. In an embodiment, the phenolic compound can berepresented by formula (III) below:

wherein R⁵ and R⁶ are each independently selected from the groupconsisting of hydrogen, an alkyl moiety comprising from about 1 to about24 carbon atoms, and a cyclic moiety comprising from about 3 to about 12carbon atoms, and R⁷ is selected from the group consisting of hydrogen,alkyl, aryl, alkaryl, and (CH₂)_(n)COOR⁸, wherein n is an integer from 1to 4, inclusive and R⁸ is an alkyl moiety comprising from about 1 toabout 18 carbon atoms. The cyclic moiety can include polycyclic ringsystems, such as bicyclic and tricyclic groups. In another embodiment,the phenolic compound can be an oligomer. In yet another embodiment, thephenolic compound can be an esterified reaction product of2,6-di-tert-butyl phenol and acrylic acid. An example of a commerciallyavailable phenolic compound suitable for use herein is3,5-di-tert-butyl-4-hydroxyphenol propionate, which is a clear, yellowto amber liquid having a viscosity of 120 mm²/s at 40° C. and a densityof 0.96 g/cm³ at 20° C. Another example of a commercially availablephenolic compound suitable for use herein is a high molecular weightoligomer of a butylated reaction product of p-cresol anddicyclopentadiene, which is a light powder or yellowish flakes having amelting point of 105° C. One example of such an oligomer is representedby formula (IV) below:

wherein n is any integer greater than 10, such as, for example, aninteger greater than about 100, or in other examples, an integer greaterthan about 1000.

The phenolic compound can be present in the disclosed lubricant andadditive compositions in any effective amount, which can be readilydetermined by one of ordinary skill in the art. In an embodiment, thelubricating composition of the present disclosure can comprise fromabout 0.05 wt. % to about 1.2 wt. %, and for example from about 0.1 wt.% to about 0.8 wt. % of the phenolic compound, relative to the totalweight of the lubricating composition. In another embodiment, theadditive composition of the present disclosure can comprise from about0.5 wt. % to about 12 wt. % of the phenolic compound, relative to thetotal weight of the additive composition.

The compositions disclosed herein can optionally contain additives, suchas phosphorus-containing compounds, dispersants, ash-containingdetergents, ashless-detergents, overbased detergents, pour pointdepressing agents, viscosity index modifiers, ash-containing frictionmodifiers, ashless friction modifiers, nitrogen-containing frictionmodifiers, nitrogen-free friction modifiers, esterified frictionmodifiers, extreme pressure agents, rust inhibitors, antioxidants,corrosion inhibitors, anti-foam agents, titanium compounds, titaniumcomplexes, organic soluble molybdenum compounds, organic solublemolybdenum complexes, boron-containing compounds, boron-containingcomplexes, and combinations thereof. In an aspect, thephosphorus-containing compounds, for example zinc dialkyldithiophosphatesalts, in the lubricant composition may be present in an amountsufficient to provide from about 100 to about 1000 parts per million byweight of total phosphorus in the lubricant composition. In anotheraspect, the phosphorus-containing compounds may be present in an amountsufficient to provide from about 600 to about 800 parts per million byweight of total phosphorus in the lubricant composition. In yet anotheraspect, the compositions can comprise various levels of at least onetitanium-containing compound depending on the needs and requirements ofthe application.

Base oils suitable for use in formulating the disclosed compositions canbe selected from any of the synthetic or mineral oils or mixturesthereof. Mineral oils include animal oils and vegetable oils (e.g.,castor oil, lard oil) as well as other mineral lubricating oils such asliquid petroleum oils and solvent treated or acid-treated minerallubricating oils of the paraffinic, naphthenic or mixedparaffinic-naphthenic types. Oils derived from coal or shale are alsosuitable. Further, oils derived from a gas-to-liquid process are alsosuitable.

The base oil can be present in a major amount, wherein “major amount” isunderstood to mean greater than or equal to 50%, for example from about80 to about 98 percent by weight of the lubricant composition.

The base oil typically has a viscosity of, for example, from about 2 toabout 150 cSt and, as a further example, from about 5 to about 15 cSt at100° C. Thus, the base oils can normally have a viscosity in the rangeof about SAE 15 to about SAE 250, and more usually can range from aboutSAE 20 W to about SAE 50. Suitable automotive oils also includecross-grades such as 15 W-40, 20 W-50, 75 W-140, 80W-90, 85 W-140, 85W-90, and the like.

Non-limiting examples of synthetic oils include hydrocarbon oils such aspolymerized and interpolymerized olefins (e.g., polybutylenes,polypropylenes, propylene isobutylene copolymers, etc.);polyalphaolefins such as poly(1-hexenes), poly-(1-octenes),poly(1-decenes), etc. and mixtures thereof; alkylbenzenes (e.g.,dodecylbenzenes, tetradecylbenzenes, di-nonylbenzenes,di-(2-ethylhexyl)benzenes, etc.); polyphenyls (e.g., biphenyls,terphenyl, alkylated polyphenyls, etc.); alkylated diphenyl ethers andalkylated diphenyl sulfides and the derivatives, analogs and homologsthereof and the like.

Alkylene oxide polymers and interpolymers and derivatives thereof wherethe terminal hydroxyl moieties have been modified by esterification,etherification, etc., constitute another class of known synthetic oilsthat can be used. Such oils are exemplified by the oils prepared throughpolymerization of ethylene oxide or propylene oxide, the alkyl and arylethers of these polyoxyalkylene polymers (e.g., methyl-polyisopropyleneglycol ether having an average molecular weight of about 1000, diphenylether of polyethylene glycol having a molecular weight of about500-1000, diethyl ether of polypropylene glycol having a molecularweight of about 1000-1500, etc.) or mono- and polycarboxylic estersthereof, for example, the acetic acid esters, mixed C₃₋₈ fatty acidesters, or the C₁₃ Oxo acid diester of tetraethylene glycol.

Another class of synthetic oils that can be used includes the esters ofdicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinicacids, alkenyl succinic acids, maleic acid, azelaic acid, suberic acid,sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonicacid, alkyl malonic acids, alkenyl malonic acids, etc.) with a varietyof alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol,2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether,propylene glycol, etc.) Specific examples of these esters includedibutyl adipate, di(2-ethylhexyl)sebacate, di-n-hexyl fumarate, dioctylsebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate,didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester oflinoleic acid dimer, the complex ester formed by reacting one mole ofsebacic acid with two moles of tetraethylene glycol and two moles of2-ethylhexanoic acid and the like.

Esters useful as synthetic oils also include those made from C₅-₁₂monocarboxylic acids and polyols and polyol ethers such as neopentylglycol, trimethylol propane, pentaerythritol, dipentaerythritol,tripentaerythritol, etc.

Hence, the base oil used which can be used to make the compositions asdescribed herein can be selected from any of the base oils in Groups I-Vas specified in the American Petroleum Institute (API) Base OilInterchangeability Guidelines. Such base oil groups are as follows:

Group I contain less than 90% saturates and/or greater than 0.03% sulfurand have a viscosity index greater than or equal to 80 and less than120; Group II contain greater than or equal to 90% saturates and lessthan or equal to 0.03% sulfur and have a viscosity index greater than orequal to 80 and less than 120; Group IlI contain greater than or equalto 90% saturates and less than or equal to 0.03% sulfur and have aviscosity index greater than or equal to 120; Group IV arepolyalphaolefins (PAO); and Group V include all other basestocks notincluded in Group I, II, III or IV.

The test methods used in defining the above groups are ASTM D2007 forsaturates; ASTM D2270 for viscosity index; and one of ASTM D2622, 4294,4927 and 3120 for sulfur.

Group IV basestocks, i.e. polyalphaolefins (PAO) include hydrogenatedoligomers of an alpha-olefin, the most important methods ofoligomerisation being free radical processes, Ziegler catalysis, andcationic, Friedel-Crafts catalysis.

The polyalphaolefins typically have viscosities in the range of 2 to 100cSt at 100°C., for example 4 to 8 cSt at 100° C. They can, for example,be oligomers of branched or straight chain alpha-olefins having fromabout 2 to about 30 carbon atoms, non-limiting examples includepolypropenes, polyisobutenes, poly-1-butenes, poly-1-hexenes,poly-1-octenes and poly-1-decene. Included are homopolymers,interpolymers and mixtures.

Regarding the balance of the basestock referred to above, a “Group Ibasestock” also includes a Group I basestock with which basestock(s)from one or more other groups can be admixed, provided that theresulting admixture has characteristics falling within those specifiedabove for Group I basestocks.

Exemplary basestocks include Group I basestocks and mixtures of Group IIbasestocks with Group I bright stock.

Basestocks suitable for use herein can be made using a variety ofdifferent processes including but not limited to distillation, solventrefining, hydrogen processing, oligomerisation, esterification, andre-refining.

The base oil can be an oil derived from Fischer-Tropsch synthesizedhydrocarbons. Fischer-Tropsch synthesized hydrocarbons can be made fromsynthesis gas containing H₂ and CO using a Fischer-Tropsch catalyst.Such hydrocarbons typically require further processing in order to beuseful as the base oil. For example, the hydrocarbons can behydroisomerized using processes disclosed in U.S. Pat. Nos. 6,103,099 or6,180,575; hydrocracked and hydroisomerized using processes disclosed inU.S. Pat. Nos. 4,943,672 or 6,096,940; dewaxed using processes disclosedin U.S. Pat. No. 5,882,505; or hydroisomerized and dewaxed usingprocesses disclosed in U.S. Pat. Nos. 6,013,171; 6,080,301; or6,165,949.

Unrefined, refined and rerefined oils, either mineral or synthetic (aswell as mixtures of two or more of any of these) of the type disclosedhereinabove can be used in the base oils. Unrefined oils are thoseobtained directly from a mineral or synthetic source without furtherpurification treatment. For example, a shale oil obtained directly fromretorting operations, a petroleum oil obtained directly from primarydistillation or ester oil obtained directly from an esterificationprocess and used without further treatment would be an unrefined oil.Refined oils are similar to the unrefined oils except they have beenfurther treated in one or more purification steps to improve one or moreproperties. Many such purification techniques are known to those skilledin the art such as solvent extraction, secondary distillation, acid orbase extraction, filtration, percolation, etc. Rerefined oils areobtained by processes similar to those used to obtain refined oilsapplied to refined oils which have been already used in service. Suchrerefined oils are also known as reclaimed or reprocessed oils and oftenare additionally processed by techniques directed to removal of spentadditives, contaminants, and oil breakdown products.

According to various embodiments, there is disclosed a method ofdelaying the onset of viscosity increase in a lubricant composition. Asused herein, the term “delaying the onset of viscosity increase” isunderstood to mean delaying the start of an increase in the viscosity ofa lubricant composition due to the oxidation process, as compared to acomposition that is devoid of the compositions of the presentapplication, including a triazole compound substituted with an arylmoiety, a nitrogen-containing compound, and a phenolic compound, asdisclosed herein. The method of delaying the onset of viscosity increasein a lubricant composition can comprise providing to a machine alubricant composition comprising a major amount of a base oil; and aminor amount of an additive comprising (i) a triazole compoundsubstituted with an aryl moiety; (ii) a nitrogen-containing compoundrepresented by formula (I):

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenoliccompound.

According to various embodiments, there is also disclosed a method oflubricating at least one moving part of a machine. As used herein, “atleast one moving part of a machine” is understood to mean at least onepart of a machine which is capable of being in motion, including a gear,piston, bearing, rod, spring, camshaft, crankshaft, and the like. Themethod of lubricating at least one moving part of a machine comprisescontacting the at least one moving part with a lubricant compositioncomprising a major amount of a base oil; and a minor amount of thedisclosed additive composition.

In other embodiments, there is also disclosed a method for operating amachine comprising adding to the machine a lubricant compositioncomprising a major amount of a base oil and a minor amount of thedisclosed additive composition.

The machine in the disclosed methods can be selected from the groupconsisting of spark ignition and compression-ignition internalcombustion engines. Moreover, the at least one moving part can be chosenfrom a gear, piston, bearing, rod, spring, camshaft, crankshaft, and thelike.

The lubricant composition can be any composition that would be effectivein lubricating a machine. In an aspect, the composition is selected fromthe group consisting of passenger car motor oils, medium speed dieselengine oils, and heavy duty diesel engine oils.

EXAMPLES

The following examples are illustrative of the invention and itsadvantageous properties. In this example, as well as elsewhere in thisapplication, all parts and percentages are by weight unless otherwiseindicated.

Compositions according to the present application were formulatedcomprising a_triazole compound substituted with an aryl moiety, anitrogen-containing compound, a phenolic compound, and a basecomposition, as shown in Tables 1 and 2. The triazole compound employedin Example Compositions 1 and 2 was a commercially availabletolyltriazole (Cobratec TT-100, PMC Specialties Group, Cincinnati,Ohio). The nitrogen-containing compound was an alkylated diphenylamine(Hi-TEC®7190, Afton Chemical Corporation, Richmond, Va.), and thephenolic compound was a commercially available transesterified phenol(Ethanox®4716, Albemarle Corporation, Richmond, Va.). A comparativeexample was formulated without a triazole compound, as shown in Table 3using the same nitrogen-containing compound, phenolic compound, and basecomposition as in Example Compositions 1 and 2.

TABLE 1 Example Composition 1 with Antioxidant System COMPONENT Wt. %Triazole 0.2 Aryl amine 0.8 Phenolic antioxidant #1 0.1 ZDDP 0.08 BaseComposition Remainder TEOST MHT-4 36.5 (mg)

TABLE 2 Example Composition 2 with Antioxidant System COMPONENT Wt. %Triazole 0.2 Aryl amine 0.4 Phenolic antioxidant #2 0.2 ZDDP 0.08 BaseComposition Remainder TEOST MHT-4 31.1 (mg)

TABLE 3 Comparative Example Composition 3 COMPONENT Wt. % Triazole —Aryl amine 0.8 Phenolic antioxidant #1 0.1 ZDDP 0.05 Base CompositionRemainder TEOST MHT-4 48 (mg)

The base composition for Example Compositions 1-3 included ingredientswithin the concentration ranges shown for Base 2 of Table 4 below. Thebase composition was formulated with a base stock meeting the GF-5standards set forth by the International Lubricants Standardization andApproval Committee (ILSAC), which in the instant example, was a SAEgrade 5 W-30 type motor oil. All values are stated as weight percent.

TABLE 4 Base 1 Base 2 Example Base Compositions (Wt. %) (Wt. %)Dispersant system 0.15–15    1–10 Metal Detergents 0.1–15  0.2–8  Corrosion Inhibitor 0–5 0–2 Metal Dihydrocarbyl Dithiophosphate 0.1–6  0.1–4   Antifoaming Agent 0–5 0.001–0.15  Friction Modifier 0–5 0–2Supplemental Antiwear Agents   0–1.0   0–0.8 Pour Point Depressant0.01–5   0.01–1.5  Viscosity Modifier 0.01–10   0.25–7   Base stockBalance Balance

A thermo-oxidation engine oil simulation test (TEOST MHT-4) wasperformed on Example Compositions 1 and 2 and Comparative ExampleComposition 3. The TEOST MHT-4 is a standard lubricant industry test forthe evaluation of the oxidation and carbonaceous deposit-formingcharacteristics of lubricants. The test is designed to simulate hightemperature deposit formation in the piston ring belt area of modernengines. The test utilizes a patented instrument (U.S. Pat. No.5,401,661 and U.S. Pat. No. 5,287,731) with the MHT-4 protocol being arelatively new modification to the test. The lower amount of depositindicates better oxidation control thereby delaying the onset ofviscosity increase in a lubricant composition.

The results demonstrated the advantage of using the disclosedcomposition to delay the onset of viscosity increase in a lubricantcomposition. As shown by the foregoing example, Example Composition 1comprising the disclosed antioxidant system demonstrated a TEOST MHT-4score of 36.5 mg. Similarly, Example Composition 2 comprising thedisclosed antioxidant system demonstrated a TEOST MHT-4 score of 31.1mg. In comparison, Example Composition 3 which did not comprise thedisclosed composition demonstrated a much higher TEOST MHT-4 score of 48mg. Thus, it can be seen that the disclosed composition surprisingly andsignificantly reduces piston deposits thereby delaying the onset ofviscosity increase in a lubricant composition.

It is intended that the examples are being presented for the purpose ofillustration only and are not intended to limit the scope of theinvention disclosed herein. As would be understood by one of ordinaryskill in the art, the particular ingredients employed and theconcentrations of the ingredients can differ from those used in theexamples. For instance, prophetic examples are contemplated which employingredients in concentrations outside of the ranges of Base 2, such aswithin the ranges set forth for Base 1 of Table 4, above.

It is noted that, as used in this specification and the appended claims,the singular forms “a,” “an,” and “the,” include plural referents unlessexpressly and unequivocally limited to one referent. Thus, for example,reference to “an antioxidant” includes two or more differentantioxidants. As used herein, the term “include” and its grammaticalvariants are intended to be non-limiting, such that recitation of itemsin a list is not to the exclusion of other like items that can besubstituted or added to the listed items.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification andattached claims are approximations that can vary depending upon thedesired properties sought to be obtained by the present disclosure. Atthe very least, and not as an attempt to limit the application of thedoctrine of equivalents to the scope of the claims, each numericalparameter should at least be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques.

While particular embodiments have been described, alternatives,modifications, variations, improvements, and substantial equivalentsthat are or can be presently unforeseen can arise to applicants orothers skilled in the art. Accordingly, the appended claims as filed andas they can be amended are intended to embrace all such alternatives,modifications variations, improvements, and substantial equivalents.

1. An additive composition comprising: (i) a triazole compoundsubstituted with an aryl moiety; (ii) a nitrogen-containing compoundrepresented by the formula (I):

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenoliccompound.
 2. The additive composition of claim 1, wherein the triazolecompound is substituted with a substituted aryl moiety comprisingmultiple rings.
 3. The additive composition of claim 1, wherein thetriazole compound is substituted with a substituted aryl moietycomprising a single ring.
 4. The additive composition of claim 1,wherein the triazole compound is represented by the formula (II):

wherein R³ is selected from the group consisting of hydrogen and analkyl moiety comprising from about 1 to about 24 carbon atoms, andwherein R⁴ is selected from the group consisting of hydrogen, an alkylmoiety comprising from about 1 to about 24 carbon atoms, and asubstituted hydrocarbyl moiety.
 5. The additive composition of claim 1,wherein the triazole compound is not an alkylbis-3-amino-1,2,4-triazole.
 6. The additive composition of claim 1,wherein the phenolic compound comprises an esterified reaction productof 2,6-di-tert-butyl phenol and an unsaturated carboxylic acidcomprising at least one double bond and from about 3 to about 24 carbonatoms.
 7. The additive composition of claim 1, wherein the phenoliccompound is represented by the formula (III):

wherein R⁵ and R⁶ are each independently selected from the groupconsisting of hydrogen, an alkyl moiety comprising from about 1 to about24 carbon atoms, and a cyclic moiety comprising from about 3 to about 12carbon atoms, and R⁷ is selected from the group consisting of hydrogen,alkyl, aryl, alkaryl, and (CH₂)_(n)COOR⁸, wherein n is an integer from 1to 4, inclusive and R⁸ is an alkyl moiety comprising from about 1 toabout 18 carbon atoms.
 8. The additive composition of claim 1, whereinthe phenolic compound is 3,5-di-tert-butyl-4-hydroxy phenol propionate.9. The additive composition of claim 1, wherein the triazole compound ispresent in an amount ranging from about 0.48 wt. % to about 5 wt. %. 10.The additive composition of claim 1, wherein the nitrogen-containingcompound is present in an amount ranging from about 2 wt. % to about 12wt. %.
 11. The additive composition of claim 1, wherein the phenoliccompound is present in an amount ranging from about 0.5 wt. % to about12 wt. %.
 12. The additive composition of claim 1, further comprising atleast one additive selected from the group consisting ofphosphorus-containing compounds, dispersants, ash-containing detergents,ashless-detergents, overbased detergents, pour point depressing agents,viscosity index improving agents, ash-containing friction modifier,ashless friction modifier, nitrogen-containing friction modifier,nitrogen-free friction modifier, esterified friction modifier, extremepressure agents, rust inhibitors, supplemental antioxidants, corrosioninhibitors, anti-foam agents, titanium compounds, titanium complexes,organic soluble molybdenum compounds, organic soluble molybdenumcomplexes, boron-containing compounds, and boron-containing complexes.13. A lubricant composition comprising: a major amount of a base oil;and a minor amount of an additive composition comprising (i) a triazolecompound substituted with an aryl moiety; (ii) a nitrogen-containingcompound represented by the formula (I):

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenoliccompound.
 14. The lubricant composition of claim 13, wherein thetriazole compound is present in an amount ranging from about 0.05 wt. %to about 0.5 wt. %.
 15. The lubricant composition of claim 13, whereinthe triazole compound is present in an amount ranging from about 0.1 wt.% to about 0.3 wt. %.
 16. The lubricant composition of claim 13, whereinthe nitrogen-containing compound is present in an amount ranging fromabout 0.2 wt. % to about 1.2 wt. %.
 17. The lubricant composition ofclaim 13, wherein the nitrogen-containing compound is present in anamount ranging from about 0.4 wt. % to about 1.0 wt. %.
 18. Thelubricant composition of claim 13, wherein the phenolic compound ispresent in an amount ranging from about 0.05 wt. % to about 1.2 wt. %.19. The lubricant composition of claim 13, wherein the phenolic compoundis present in an amount ranging from about 0.1 wt. % to about 12 wt. %.20. The lubricant composition of claim 13, further comprising at leastone additive selected from the group consisting of phosphorus-containingcompounds, dispersants, ash-containing detergents, ashless-detergents,overbased detergents, pour point depressing agents, viscosity indeximproving agents, ash-containing friction modifier, ashless frictionmodifier, nitrogen-containing friction modifier, nitrogen-free frictionmodifier, esterified friction modifier, extreme pressure agents, rustinhibitors, supplemental antioxidants, corrosion inhibitors, anti-foamagents, titanium compounds, titanium complexes, organic solublemolybdenum compounds, organic soluble-molybdenum complexes,boron-containing compounds, and boron-containing complexes.
 21. Thelubricant composition of claim 13, further comprising at least onetitanium-containing compound.
 22. The lubricant composition of claim 13,further comprising a phosphorus-containing compound in an amount rangingfrom about 100 to about 1000 ppm of total phosphorus in a lubricantcomposition.
 23. The lubricant composition of claim 22, wherein thephosphorus-containing compound is in a concentration ranging from about600 to about 800 ppm of total phosphorus in the lubricant composition.24. The lubricant composition of claim 13, wherein the lubricantcomposition is selected from the group consisting of passenger car motoroil, medium speed diesel engine oil, and heavy duty diesel engine oil.25. A method of delaying the onset of viscosity increase in a lubricantcomposition, said method comprising: providing to a machine a lubricantcomposition comprising a major amount of a base oil; and a minor amountof an additive composition comprising: (i) a triazole compoundsubstituted with an aryl moiety; (ii) a nitrogen-containing compoundrepresented by the formula (I):

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenoliccompound.
 26. The method of claim 25, wherein the machine is selectedfrom the group consisting of spark ignition and compression-ignitioninternal combustion engines.
 27. A method of lubricating at least onemoving part of a machine, said method comprising: contacting the atleast one moving part with a lubricant composition comprising a majoramount of a base oil; and a minor amount of an additive compositioncomprising: (i) a triazole compound substituted with an aryl moiety;(ii) a nitrogen-containing compound represented by the formula (I):

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenoliccompound.
 28. The method of claim 27, wherein the machine is selectedfrom the group consisting of spark ignition and compression-ignitioninternal combustion engines.
 29. A method of operating a machinecomprising: adding to the machine a lubricating composition comprising amajor amount of a base oil; and a minor amount of an additivecomposition comprising: (i) a triazole compound substituted with an arylmoiety; (ii) a nitrogen-containing compound represented by the formula(I):

wherein R¹ and R² are each independently selected from the groupconsisting of at least one aryl moiety comprising from about 6 to about30 atoms, hydrogen, halogen, hydroxy, hydrocarbyl, substitutedhydrocarbyl, amino, amido, phosphoro, and sulfono; and (iii) a phenoliccompound.
 30. The method of claim 29, wherein the machine is selectedfrom the group consisting of spark ignition and compression-ignitioninternal combustion engines.